All urban drainage networks are designed to manage a maximum rainfall. This situation implies an accepted flood risk for any greater rainfall event. This risk is often underestimated as factors such as city growth and climate change are ignored. But even major structural changes cannot guarantee that urban drainage networks would cope with all future rain events. Thus, being able to forecast urban flooding in real time is one of the main issues of integrated flood risk management. Runoff and hydraulic models can be essential elements of flood forecast systems, as an active part of the system or as studying tools. This paper gives an overview of current available options for pluvial flood modelling in urban areas, from basic estimations with a onedimensional urban drainage model to detailed flood process representation with one dimensional-two dimensional hydrodynamic coupled models. Each type of modelling solution is described with pros and cons regarding urban flood analysis. The paper then elaborates on real-time flood forecast systems and the influence of their main components. A classification of real-time urban flood systems is given based on the use of urban models, i.e. empirical scenarios, pre-simulated scenarios and real-time simulations. A review of existing operational systems is done using this classification.

Populations in urban environments are extremely mobile throughout the day and in various weather conditions; accounting for this pedestrian mobility and security becomes of high importance. Research into the security and stability of the pedestrian environment under exposure to critical water flows provides an essential knowledge base with which the associated hazard unto them can be critically evaluated. This research seeks to analyse degrees of hazard in relation to persons exposed to high volume rain events in urban areas. Several human trials of critical urban flows were conducted in order to determine the stability limits of pedestrians, crossing through a water flow in a real scale physic model. Additionally, the critical first step from a dry footpath into fast flowing water is considered and an assessment of the tested subjects' emotional responses when entering and crossing flooded roadways was carried out. Results from this study are compared with various proposed human stability criteria as well as alternatives proposed in other written works. The presented study offers a stability threshold focused on shallow depths and high velocity conditions, the most common urban flooding conditions. Keywords: Urban flood risk; hazard; drainage system; pedestrian stability. 11When designing drainage systems, the dual drainage concept should be considered (Djordjevic 12 et al. 1999; Nasello and Tucciarelli 2005; Concha and Gómez 2009; Nanía et al. 2015 Table 3. 150Critical storm events do not occur in a regimented manner, they can occur at any time of day. 188 High hazard: The tested subject lost stability completely. 189 Medium hazard: The tested subject showed a great difficulty in carrying out the complete 190 protocol. The subject needed to make a great effort. Slowness, stumbles, slips and a loss of one 191 or both shoes were other issues to consider a case as a medium hazard. 192 Low hazard: Small or inestimable instabilities were observed. The tested subject was able to 193 carry out the complete protocol without any inconvenience. 201In a total of 2345 assessed test cases, the number of high hazard scenarios, determined through a 202 complete loss of stability, amounted to 38, 1.6% of the total cases. This may seem as a very low number 203 of cases, however, the assessment of a high hazard situation was very rigorous and only account for 204 instances where there was a complete loss of stability and fall (Figure 8). There were multiple instances 205 where subjects lost balance but were able to recover their footing and continue without having fallen. 206These scenarios are classified as medium hazard as no fall occurred. 220The answers regarding the main points are summarized and listed below: 221(1) Discomfort caused by the safety equipment: All the respondents agreed that the comfort of the 222 safety equipment was good enough and it did not prevent to them from carrying out the tests 223 naturally. 224(2) Duration of the tests: The tests duration was adequate according to mo...

ABSTRACT:The evaluation of the possible climate change influence on extreme precipitation is very interesting in the Mediterranean area due to the usual and characteristic high intensities of its rainfall pattern. This analysis is also very important in urban zones, especially those densely populated with complex sewer systems, generally vulnerable to torrential rainfall. In this work, a total of 114 simulated daily rainfall series, 84 for the period 2000-2099 and 30 for the control period 1951-1999, have been analysed. These series were obtained for six thermo-pluviometric stations located in the metropolitan area of Barcelona using the information provided by five general circulation models under four future climate scenarios of greenhouse gas emissions and applying statistical downscaling methods. The potential changes in the intensity-duration-frequency relationships due to climate change have been investigated. For the last third of the 21st century, under A1B, A2 and B2 climate scenarios, an increase of at least 4% has been found on the expected daily rainfall with return period longer than 20 years. Using a temporal downscaling based on scaling properties of rainfall, future hourly extreme rainfall has been estimated. For almost all the scenarios and periods considered, the increase on the expected hourly rainfall has resulted slightly higher than the corresponding daily rainfall. The greatest differences between the future hourly and daily rainfall estimated have been found in the second third of the century under scenarios A1B (8%) and A2 (9%).

Urban floods are sudden phenomena normally characterized by short flooding durations and devastating effects due to the high concentrations of persons, goods, and properties located in urban areas. In these cases, uncontrolled runoff can flow on urban streets, creating a significant hazard for pedestrians and vehicles. The safety of people can be compromised when they are exposed to flows that exceed their ability to remain standing or to traverse flow paths. With the aim of studying the stability of pedestrians in flooded street during storm events, a model representing an urban street in real scale was designed and built. Following a specific protocol that considering several flow rates (up to 500 l/s) and different longitudinal slopes (up to 10 %), 834 tests, using 23 human subjects, were carried out in good and poor light conditions. Hazard conditions were classified into three groups (low, medium, and high), and the parameters for which these conditions occurred were recorded. Results showed that for subjects weighing 50–60 daN (50–60 kg mass) and flow depths between 9 and 16 cm, velocities of 1.5–2 m/s can generate loss of stability due to phenomena of dragging or overturning. Empirical expressions were proposed to relate human subject characteristics (weight and height) and limiting flow conditions at which loss of stability occurs.Postprint (published version

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